49ers' depleted defense will find out where it stands in Dallas

But he'll be facing a depleted 49ers defense in Sunday's season opener, regardless of whether Ray McDonald is allowed to play a week after his domestic-violence arrest.

"No one player makes that defense," Romo said Wednesday on a call with Bay Area media.

The 49ers defense is missing more than one player from a unit that's ranked among the three hardest to score against each year since 2011.

Romo won't be getting sacked Sunday by Aldon Smith, who is suspended the first nine games. Also missing will be linebacker NaVorro Bowman (knee) and nose tackle Glenn Dorsey (biceps), likely into November for both players.

Factor in McDonald's undetermined status -- though he's practiced the past two days -- and the 49ers defense is in flux heading into "Big D."

"We're losing some key guys. We have every right to question and be worried," linebacker Patrick Willis said. "But we're not going to do that."

In the reworked secondary, cornerbacks Tramaine Brock and likely Chris Culliver will make their first opening-day starts, and strong safety Antoine Bethea will be seeing his first action since an Aug. 17 concussion.

Romo, who rallied the Cowboys to a 2011 win over the 49ers, still respects the defense he'll encounter.

"They're a collection of outstanding individual talent with a very good scheme that can create issues with the way that they're doing things," Romo said.

Romo may not be fazed, but should the 49ers be concerned over their lack of continuity?

"If I said no, I'd be lying to you," Bethea replied. "We've still got a game to play. Dallas is not worried about what's going on here."

Cowboys coach Jason Garrett actually is concerned, but more so about how daunting the 49ers defense remains.

"It's arguably the strength of their team, and they do a fantastic job from top to bottom," Garrett said. "They have a track record of playing different guys who just come in and play, and they play at the same level."

Dan Skuta is listed on the depth chart as Smith's replacement at outside linebacker, though Corey Lemonier will be summoned to rush after Romo on passing downs. Michael Wilhoite is listed in Bowman's spot. If McDonald isn't in the lineup, Dallas-area native Tony Jerod-Eddie likely will start.

With so many changes on defense, will Colin Kaepernick and the offense be capable of carrying the 49ers?

"We have the ability to do that," Kaepernick said. "But we have great defensive players still on that field. So I don't think there'll be a drop-off."

Added Willis: "You can look across the board and find every reason to run the other way or find excuses why we can't be as good. At the end of the day, you're only as good as the guys that are out there on the field, anyway."

Harbaugh said he is awaiting "information and fact" to determine McDonald's fate. McDonald joined practice 20 minutes late, possibly after meeting with team officials. He was arrested Sunday after police determined the alleged victim, apparently his fiancee, had "visible injuries."

Harbaugh reiterated he has no tolerance for domestic violence. Then he cited the U.S. Constitution's Fifth Amendment and noted: "We all live in America. We all understand that sometimes patience is required when it comes to due process."

NFL commissioner Roger Goodell ﻿also said that before the league imposes any potential discipline, he'll wait for the legal process to play out for McDonald.

"We don't (know the facts) right now, and we're obviously following it very closely," Goodell told USA Today at a youth football event in Renton, Wash.

Wide receiver Michael Crabtree (calf) and right tackle Anthony Davis (hamstring) worked out in the weight room rather than participate in practice.